Science Briefing

Antarctica's ice gives new clues

New information on Antarctica's regularly melting distant past is giving scientists a glimpse into what may be a flooded future as the planet warms up.

The West Antarctic ice sheet collapsed periodically 3 million to 5 million years ago, adding more than 16 feet to global sea level, according to the first examination of soil cores of the Ross ice shelf. New computer models suggest that warmer waters attacked the ice from below, triggering those collapses. The findings were published Thursday in the journal Nature.